def return_dec(flag):
    def decorator(fn):
        def inner(a,b):
            if flag==0:
                print('add')
            elif flag==1:
                print('minus')
            return fn(a,b)
        return inner
    return decorator

@return_dec(0)
def conculate(a,b):
    result= a +b
    return result

print(conculate(1,2))